The present invention pertains to the field of recombination lasers.
Only a few of the thousands of atomic laser transitions already discovered have achieved efficiencies greater than 1 percent. For example, the He-Neon laser at 6328 A is perhaps the most well-known example of a neutral atomic species laser, but its efficiency is less than 0.1 percent. Commercially available Helium-Neon lasers typically require 10 W or more of electrical power to provide 1 or 2 mW of laser power at 6328 A. The copper laser, probably the only neutral atomic laser with an efficiency above 1 percent, having yielded efficiencies as high as 2 percent, has problems in achieving long life at such efficiencies due to the difficulty involved in generating the required densities of copper vapor. In addition, the short pulse length and high gain further restrict the use of the copper laser.
Most neutral atom lasers which are excited by an electrical discharge are inefficient because the excitation energy produced by the electrical discharge excites a large number of states, each of which states can decay via a number of different decay paths.